For decades, the standard veterinary advice for feline Chronic Kidney Disease (CKD) was simple: slash the protein. The logic was that since the kidneys are responsible for filtering out the nitrogenous byproducts of protein metabolism, eating less protein meant less “work” for the kidneys.

However, as we move into 2026, the narrative has shifted. We now know that for senior cats, protein restriction is a double-edged sword. While it may lower blood urea nitrogen ($BUN$), excessive restriction often leads to Sarcopenia—the devastating loss of skeletal muscle mass. A senior cat with CKD who loses too much muscle becomes weak, lethargic, and loses their quality of life.

The modern goal is Precision Nutrition: providing the highest quality protein to maintain muscle, while strictly controlling the real culprit of kidney decline—Phosphorus.

The Biological Value of Protein: Quality Over Quantity

Not all proteins are created equal. In nutrition, we …